Dwelling assembled from prefabricated units



Nov. 2, 1937. J. H. KENNEDY DWELLING ASSEMBLED FROM PREFABRICATED UNITS Filed March 2, 1934 4 sheets-sheet 1 1|||||l||. l l l l l l I l l I l i I l l l I I I I l f I I l I I l llIlili-...IIIIIHIHHI I fill.

INVENTOR J. H. KENNEDY DWELLING ASSEMBLED FROM PREFABRIGATED UNITS Nov. 2, 1937.

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INVENTOR Nov. 2, 1937. J. H. KENNEDY- v 2,097,796

lDW`r'}I.|L|INGr ASSEMBLED FROM PREIABRICATED UNITS i I Filed March 2, 1.934 4 Sheets-Sheet 3 INVENTOR Nov. 2, 1937. J. H. KENNEDY DWELLING ASSEMBLED FROM PREFABR-ICATED UNITSl Filed March 2, 1934 4 Sheets-Sheet 4 50 Oxy-salt cement.

Patented Nov. 2,1937 y DWELLING ASSEMBLED lFROM PREFABRI- CATED UNITS James H. Kennedy, Lansdowne, Pa., assignor to Magnesium Cement Laboratories, Inc., Philadelphia, Pa., a corporation of Pennsylvania Appucaaon Maren z, 1934, serial No. 713,664 19 claims. icl. 'zzp- 16) This invention relates to the construction of small buildings, such as dwellings, from units which are prefabricated and so far finished in the factory that the units may be assembled and erected with a minimum 'of labor and skill at the site of the dwelling. More particularly, this invention relates to expedients for simplifying the installation or assembly of the prefabricated units or panels which, to a large extent, go to l0 makeup the floors, walls, ceilings, and even the roof of a dwelling constructed in accordance with my invention. 1

In erecting light and inexpensive structures in accordance with my invention, a narrow elonl" gated structural unit is the most important element. I prefer to produce such a unit byA rst forming a body or core of fibrous material bonded by magneslum-oxy-salt cement such as magnesium-oxy-chloride cement or magnesium-oxy- 30 sulphate cement, or a mixture of Oxy-chloride and Oxy-sulphate with magnesium. A number of flbrous materials, such asbagassecornhuskastraw, wood shavings, chips, and shredded wood (otherwise known as excelsior) are suitable for this 25 purpose; but I have found that best results are `to be obtained by using one of the several grades of excelsior such as wood wool', standard ex- `celsior or coarse excelsior. 'Ihe mixture of aggregate and cementitious material is distributed on a platten and compressed, the pressure being maintained until the cement has set to such a stage that the compressed material will not ex pand upon release of the pressure. 35 This body or core of bonded compressed fibrous material is covered on either or both sides by a surface layeror layers of denser material. This denser material `is preferably applied after the core has been dried and cured. A typical mate- 40 rial for the surface layer, ii.'` the same is to be exposed to the Weather, is made up as a stucco from a suitable aggregate and magnesium-oxysalt cement. This stucco, after being applied, may be coated in the factory with a penetrating, wa- 5 ter repellant substance.

A typical composition for the surface layer, if the same is -tq be exposed in the interior of the dwelling, is avmixture of sand, Silex, asbestos, lithopone and a water-proofer and magnesium- T'hese surface mixtures are, in

plastic condition, applied to the surface of the core, either by hand or'by machinery; and linish'ed in any finish desired; and if the cores are properly made with an open texture, the surface' layers will become anchored to the core so that the unit is practically a homogeneous mass. Suitable panels for my purpose, and a preferred manner of producing such panels are `disclosed in my copending application Ser. No. 713,663,l

led March 2 1934. The present invention re- 5 lates to features of construction which simplify the erection of light buildings, such as inexpensive dwellings, using prefabricated units of the above-described type.

In the accompanying drawings in which I il- 10 lustrate certain embodiments of my invention for the purpose of illustrating the same,

Fig. 1 is a side view of a light, inexpensive dwelling erected by assembling prefabricated units; 15

Fig. 2 is a vertical section illustrating the foundation, the floor, a portion of an outer wall, and a portion of a partition wall;

` Fig. 3 is a detail view partly in cross-section and partly in end elevation. of means `for posi- 20 tioning a joist;

Fig. 4 is an end view, partly in section, of a clip for securing a floor panel to the flange of a beam;

Fig. 5 shows in vertical section a modified construction for supporting the ceiling;

Fig. 6 shows in vertical section a further modifled construction for supporting the ceiling;

Fig. 'l is a plan View of a bearing plate located` at the top of a corner for positioning angularly related panels;

Fig. 8 is a plan view of a rounded corner member.

The dwelling shown in Fig. 1 of the drawings is of the bungalow type having a foundation I Il cast on a looting II. vThe foundation Il) is cast with an offset or'shelf I3 adjacent the upper portion thereof on which may rest the ljunior I-beams l5. 'I'hese I-beams do not extend the 40 full distance from one outside wallto the other, l but are somewhat over half this length, being supported intermediate the outside walls by a` central foundation I6 with a flat top. As shown in Fig. 2, the foundation I0 has the oisetrlli 45 formed in Ysuch dimensions that the ends of the I-beams abut against the upwardly projecting portion I8, thus determining the position of the beams or joists longitudinally. Obviously, the I-beams I5 overlap on the central foundation i6. 50

The I-beams are positioned laterally by the bearing plate and yokes shown in Figs. 2 and 3. The bearing plate 20 is provided with four openings for receiving the legs of two yokes 2|. The ends 22 of the-legs are provided with means 23 55 the ends 22 of the legs of the yokes; but obviously any other suitable form of anchoring means may l be used. 'The legs 22 and anchoring means23 are-embedded in the foundation in the process of casting the same, and the plate 2D accurately vpositioned to the proper level, grouting being employedV if necessary to accurately position the plate 20. The openings in the plate are so spaced that the base ange of the I--beam I5 is received between the pair of yokes with a close i'lt, the yokes at that time being in the position shown in dotted lines in Figs. 2 and 3. As shown in the drawings, a plate 28 furnished with a pair of yokes 2l is at each end of an I-beam I5 to position the same.y When the I-beam has been lowered into place resting on the two plates 20,

the yokes are bent inwardly and downwardly over the base flangel of the Lbearn, as shown by the full line position, to hold the same in position.

The yokes 2| are fashioned of steel which can ber thus deformed by a press or by blows from a sledge hammer.

It will be noted that the top surface of the upper ange of the I-beam I5 is nearly flush-with the top of the upwardly projecting portion I8 of the foundation. For tightness against drafts, it will be desirable to spread packing or cement on top of the portion I8 to receive the outer border of a floor panel 26. One or more bolts 21 cast in the portion I8 extend throughy openings formed in the panel 26 in such position that when registering with the bolts 21 the outer edge of the panel 26 is substantially ush with the outer face of the foundation I0.

The long kdimension of the panel 26 extends transversely of the I-beams or joists I5, and thus runs lengthwise of the foundation I0. A flat clip 28 may be attached to the side edge of a panel 26 by nails'or screws driven through openings 28a in the clip into the body or core of the panel. 'I'he clip 2B, as shown in Fig. 4, hasa cleft 28h conforming to the beam flange; and when the clip is so secured to a panel 26 that the cleft 28h receives the flange of a beam I5, the panel is securely held thereto. An additional opening 28e is provided in the clip for attaching the clip to the web of beam. as by wiring.

'Ihe panels are ofstandard construction and provided with a groove 29 in each of the lateral edges. The groove inthe inner edge of the panel 26 is made use of for aligning the panel with the adjoining panel 26'. For this p'urpose, a spline 30 of hardwood or of bonded aggregate of such character as to have high insulating value is received in the mating grooves 29 -of the adjoining panels'26and 26'. Preferably, this spline 30 will 4be cemented in the groove to make the joint 3II between panels air-tight. With sucha form of joint, using a` spline which has high insulating value, the floor will be uniformly insulated throughout its area.

The external border of the panel 26 which rests'on .top ofthe portion I8 of'foundation I0 is closed in by a rustless metal fastener 33 having a rib 34 @conforming to the groove 29 and received therein, thus positioning this fastener relativeto the` panel 26. The lower portion or skirt 35 of the fastener 33 extends down over the packing or cement 25. thus shutting out rain and helping to make the structure tight. The fastener 33 is bent inwardly at the upper corner of the panel 26 and is shaped with a tongue or spline 31 overlying the upper end of the bolt 21. This spline 31 constitutes a positioning means which is received in a groove in the base of a vertical wall panel 38. The fastener 33 being securedvto the floor, its tongue 31 thus positions the panel 38 relative to the floor. It'will thus be apparent that by properly positioning the bolts 21 in the portion I8 of the foundation, the floor panels 26 will be positioned without further measurement, and the Wall panels 38 will likewise be positioned. This simplies the assembling of the panelsto construct the buildings, by making it necessary to accurately measure only the position of the offset or shelf I3 and the positions of the plate 26 and the bolts 21, after which the floor and side walls of the dwelling can be placed by unskilled workmen. After the oor panels 26, 26', etc. have been laid. the finished floor surface 40, such as hardwood flooring, tile or linoleum, may be laid on top of the panel and secured thereto. Certain types 'of nish, however, may be placed on the floor panels in the factory so that when these panels are laid, a finished flooring is provided. A

In order to make provision for a base board, it is desirablefthat the metal fastener 33 be extended inwardly under the inner edge of the panel 38 and then upwardly along the face of the wall to a proper height, after which the fastener is bent downwardly to form a base board portion 4I. The edge 42 of the fastener may be v rccurved to form a rounding edge resting on the finished oor 40. The space behind the portion 4I is available for tubing 43 within. which the electric light wires may be carried tothe usual outlets provided either in the base board or in the wall. The rustless metal fastener 33, because of its shape, can be more easily rolled in two sections, these sections being assembled with the panel 26 sov that the edges overlap within the groove in the base of the panel 38. This assembling is carriedfout in a very simplemanner, and skilled labor is largely eliminated. After installation, the exposed joints may be made tight with water-proof compound.

The wall panels 38 are provided with a groove not only inthe base but also in the lateral edges. Accordingly, adjoining wall panels 38 are aligned by splines which are cementedin the grooves, just as described in connection with the flooring. Preferably, the vertical joint' between adjoining wall panels 38 is pointed up. I'he outside face of the panel 38 willconsst. of a material prooi` against the weather, such as a stucco or artificial stone composition. The inside surface layer of the panel 38 can take such embodiment as ts in with the decorative scheme, whether it be plastering, tiling or other suitable finish. The most suitable lmaterial for the core of the panel being a compacted bonded aggregate, preferably fibrous material and magnesium-oxy-.salt cement -as above described, it is of distinct advantage to-use this same cement as the bonding ingredient of the outer and inner surface layers so that the coeffi- -cient of expansionof the cement throughout the panel is substantially the same.

There is considerable flexibility in the cnstruction of a dwelling such as above outlined. Certain of the splines may be omitted so as to leave passageways such as the one shown at 46. This passageway consists of the mating grooves 29 in adjoining panels, and is large enough to carry a pair of pipes. VIn the panels of larger dimensions, half inch pipes or larger canv be carried in the passageway 46. Such a passageway vmay even be provided in the side wall of the dwelling by comme groove in thebase of the partition panel engages this spline or-tongue so that the partition is accurately positioned. -These partitions may, as

. shown in Fig. 5, be placed on a packing 48 of felt,

or on a layer of Keilgur (an articial rubber which is hi-ghly resistant to oxidation), rubber or other material which insulates -against sound. In this waya sound-proof partition may be erected in a building such as a hospital with minimum expenditure for labor; and there is the posl sibility of recovering the panels practically intact if it is desired to remove the partition. The spline 41 shown in Fig. 5 is tapered vertically so as to assist in engaging the groove in the base of the panel with this spline, and to make the panel more readily removable. While the base board 48 shown in this figure is entirely exterior of the partition wall, being secured in place by a nail orscrew 50, it is obvious that this base board might be formed of sheet metal with an inwardly bent portion to extend into the groove in the base of the partition panel in similar fashion to the base board shown at 4I in Fig. 2.-

The insulating layer 42 at the top of the partition prevents the transmission ofsound Waves between the side wall and the ceiling. The groove 53 in the top of the panel is useful in positioning the panel relative to the ceiling. For this purpose, a bolt 54 is extended through an opening in the ceiling panel 55, with the lower end of the bolt secured in a strip of rigid material 56 which is entered in the groove 53. A head 51` on the projecting end of the bolt 54 secures this assembly to the ceiling -panel 55. Prior to assembling, a combined hanger and bearing plate 58 maybe slipped in place on the upper end of the partition panel with the inner ange 59 extending down into the groove 53. The hanger 58 may be formed as picture molding for decorative purposes. The strip 56 entered in the groove 53 positions the top of the partition panel relative to the ceiling panel 55.

The ceiling panels 55 may be of standard construction with grooves 6| in`the lateral edges thereof to receive a spline 62. Use may be made of the spline 62 for hanging the ceiling from the roof structure, such as the joists or beams 63. For thisjpurpose, the splines 62 may be suspended by'wires 64 from the joists 63. With this construction the supporting structure for the ceiling is completely hidden so that there are no battens exposed on the underside of the ceiling.

On the other hand, if for 4decorative purposes a batten is desirable, a combined` spline and hanger 65 may be entered in the mating grooves of adjoining panels. An extension 66 of the spline protrudes from the joint and is shaped as a batten to overlie the joint. .Wires 61 hung from the joists or beams suspend the combined spline and hanger 65'from the roof structure, the hanger being caught to the wire by a key 68 or the like. In both of these forms of ceiling suspension, the spline may be cemented in the grooves for added tightness and greater structural strength. If the spline is of insulatingmaterial, the ceiling will have uniform insulating value throughout its area.

In the form of ceiling construction shown in Fig. 6, the panels 18 are aligned by'splines 62 which may be of insulating material if desired and cemented inthe grooves 6I for greater structural strength. The top sides of the panels 18 are recessedat v12 to receive inverted perforated metal channels or yokes 13. These short perforated channels are cemented in the recesses 12 and thus ilrmly anchored in the-ceiling panels. Wires 14 thrust through the channels 13 suspend the ceiling from the joists or beams of the roof structure.

It is not always necessary to provide a supporting structure for the' ceiling, such as the rafters or beams referred to in describing the constructions illustrated in Figs. and 6. Where the room is small, the panels forming the side walls oi.' the room may carry the weight of the ceiling, and even of the roof. In such case, the splines 62 entered in the grooves 6I should be cemented in place to strengthen the structure.

A bearing plate, such as shown at 16 in Fig. 7, may be placed on top of the side walls at the corner of a room to position the anguiarly related panels 38 relative to each other. 'Ihe bearing plate 16 carries aligning means depending into the grooves 11 in the top edges of the panels 38. As illustrated in Fig. '7, the aligning means takes the form of a perforated metal channel 18 depending into the groove 11 from the plate 16. The bearing plate 16 will usually carry suilicient load so that it is improbable that the aligning means would be dislodged from the grooves 11.'

However, I find it preferable to use cement in the grooves 11 so as' to anchor the inverted channels 18 in place inthe grooves. In some instances, the aligning means may be'punched in rounded corner member 88 of polished stainless steel. The arc of the rounded corner member 80 may be about 90, or slightly more or less.

In forming the corner member from a sheet of steel, the sheet `may be bent back at 8| so as to provide rounded ends for the member, the anges being bent across the end faces of the panels L38. One edge of the sheet mayl be bent in the shape of a channel 83 tightly tting the vertical groove 84 in the panel. 'I'he otherl edge of the sheet may be bent into a spring clip 85, V-shaped in cross-section. The channel-shaped portion 83 will be pushed into its groove 84 in assembling the member 88 with the pair of panels 38. In so assembling the member 88 with the panels, the clip 85 springs into-the groove-'84 of the other panels. Cement or water-proof compound .may be used to point up the joint behind the panels reduce the labor costs and provide a durable and attractive structure which isecobe a bearing or a non-bearing lwall, can be made' up entirely of my improved panels. A part or `all of the weight of a superstructure such as a4 roof or ceiling can be carried by a bearing wall made up entirely of such panels.

While I have illustrated and described certain l embodiments which my invention may assume,

it will be understood that the invention is not Y restricted to the -particular constructions and arrangements shown but may be variously modified within the contemplation of the invention and under the scope of the following claims.

I claim:

1`. In combination in a prefabricated dwelling, a structure and a ceiling hung therefrom comprising a plurality of panels with grooves in adjacent edges, and Ameans for supporting rsaid panels comprising a preformed spline cementedV .in the grooves of adjacent panels and va suspension device connecting the spline and structure. 2. The combination as set forth in claim 1 in which the panels have each a 'core of compacted bonded fibrous material and atleast one surface layer of denser material.

3. In combination in a prefabricated dwelling,

a structure, and a ceiling hung therefrom comprising a plurality of panels with grooves in adjacent edges, a spline cemented in the grooves of adjacent panels and a hanger for suspending said spline from said structure.

' 4. In combination, a structure, and a ceiling hung therefrom comprising a plurality of `panels with grooves in the upper sides thereof, channels Y cemented in said grooves, and means Tior suspending said channels from said structure.

5. In combination, a structure, and a ceiling hung therefrom'comprising a.. plurality of panels with grooves in the upper sides thereof, said panels having each a core of compacted bonded l vfibrous material and at least one surface layer of denser material, channels cemented' inA said grooves and means for suspending said channelsrfrom said structure.

6. In combination in a prefabricated dwelling, a floor comprising a plurality of panels positioned edge to edge with grooves in theiadjoiningfedgas, a spline seated in adjacent grooves and a conduit received 4in one .of said grooves so as to be invisible from above or below the ,panels 'said floor being arranged to resist bending strains from loads thereon. Y

7. In combination in fa prefabricated-dwelling, a floor comprising joists, a v.plurality v.of grooved panels directly supported on said joints edge to edge, means inserted vlietween and held to adiacent panels for securing Athe panels to the .ioists, and means for aligning said panels comprising a spline entered'in grooves in adjoiningedges `oi. adjoining panels. l

8. A floor structure comprising Aa plurality v:of elongated fiat units having a body or core of compacted bonded fibrous material and a layer of covering material on at least one face thereof, a transverse supporting element` for zcarrying epargne said imlts flatwise in vadjoining yrelationQavnd a nat clip inserted between the edges of adjoining units for attaching. a unit to the supporting element, said clip being secured by fasteners exfor attaching the unit in ilatwise relation to said transverse supporting element, said clipheingy secured by fasteners extending into the body or l. core of a panel.

l0. In combination in a structure, a plurality of adjoining panels mounted edge to edge, the mating grooves in-adjoining panels forming a concealedvrecess extending longitudinally within the borders of said panels,.means for aligning said panels comprising a spline received in one of said longitudinal recesses, and conducting means for fluid received in one 0f said longitudinal recesses.

l1. A Wall structure comprising prefabricated structural sections forming a complete wail structure, each section-comprising a plurality of spaced-apart layers of bonded aggregate and cement of sufficient thickness to afford material structural strength, said layers being secured tothe Apanels having grooves along their lower edges, and a spline device engaging the registering grooves of the successive panels.

12.'A wall structure comprising prefabricated structural sections forming a complete wall structure, each section comprising a plurality of spaced-apart layers of bonded aggregate and cement of sufficient thickness to afford material `structural strength, said layers being secured together by a less dense. and more porous core 'of bonded brous material extending to thev ends of the section andv having exposed edge portions, the panels having grooves along their lower edges', and a spline device engaging the registering grooves of the successive panels, said spline having a base portion extending beyond a face of 'a panel.

13. A wall structure comprising prefabricated structural sections forming a complete wall structure, each section comprising a plurality voi' spaced-apart layers of bonded aggregate and .cement of sufficient thickness to afford material structural strength, said layers being secured gether by a less dense and more porous' core of together by a ,less dense and more porous core of bonded fibrous .material extending, to the ends of the section and having expiised edge portions, the panels having grooves along their lower edges, and a spline device-engaging the registering grooves of lthe successive panels, said panels having vertically extending edgegrooves with splines secured therein.

v.14. I'he combination in a `iloor structure of a plurality of horizontally arranged joists, a set of panels laid edge-to-edg'e on said joists, each panel comprising a plurality of spaced-apart layers of bonded aggregate of sumcient thickness to afford material structural strength, said layers being secured together 'by a less dense and more porous core of bonded nbrous material extending to .the ends of the section and having exposed edge portions,the adjacent Aedges of being secured together by a less denseand more porous core of bonded brous material extending to the ends of the section and having exposed edge portions, the cores having edge y grooves, and-splines secured in said grooves of the floor and wall.

16. The combination in a. wall structure of a support, a set of panels mounted thereon, each panel consisting of a prefabricated structural section comprising a plurality of spaced-apart layers of bonded aggregate of suicient thickness to aord material structural strength, said layers being secured together by a less dense and more porous core of bonded fibrous material extending to the ends of the section and having exposed edge portions, the panels having registering bottom grooves, and registering vertically extending edge grooves with splines secured'in the vertically extending edge grooves of the adjacent panels.

17. In a building suitable for a dwelling, a wall comprising a plurality of similar prefabricated structural sections comprising a complete wall unit, each section comprising a plurality of spaced-apart layers of bonded aggregate of sufilcient thickness to afford material structural strength, said layers being secured together by a less dense and more porous core of bonded brous material extending to the ends oi' the section and having exposed edge portions, the edges of said sections being interlocked, and said unit being of sui'licient strength to carry the weight imposed upon said wall unit.

' 18. In a building suitable for a dwelling, a wall lcomprising a, plurality of similar prefabricated structural sections comprising a com plete'wall unit,eachsection comprising a plurality of spacedapart layers of bonded aggregate of sulcient thickness to aiord material structural strength, said layers being secured together by a less dense and more porous core of bonded ilbrous material 15 extending to the ends of the section and having exposed edge portions, the adjacent edges of said sections having registering grooves, and splines permanently secured Within said grooves.

19. A wall structure comprising prefabricated 20 structural sections forming a complete wall structure, each section comprising a core oi' bonded iibrcus material extending to the ends of the sectionrand having exposed edge portions, and having a plurality of spaced-apart layers of 25 bonded aggregate and cement of sufiicient thickness to afford material structural strength to the section, said facing layers being more dense and less porous than the bonded fibrous core which secures them together, the bondedbrous 30 cores having grooves, and a spline device engaging registering grooves of the cores of .successive sections.

JAMES H. KENNEDY.

CERTIFICATE or. coRREc'rI-ON.

latent No. 27,097,796.

JAMES H.

KENNEDY Novanber .2,I Y'?u It is hereby certified that error appears inthe printed specification ofthe above numbered patent requiringeorrection as follows: Page il, first column., line 65, claim', for the word "'joints'i read joists; and that the said Letters Patent should be read with this correction thereinthat the same may conformr'to the record of the case inthe Patent Office.

signed and seaied this 12am day of December, A. D. 1957.

(seal) Henry Van :Arsda1e, Actirg Commissioner of" Patents.

said oor panels being grooved and splines secured within the registering grooves thereof.

15. I'he combination in a prefabricated structure, oi' a oor portion and a wall portion coacting therewith, said portions each being formed of prefabricated structural sections, each section comprising' a plurality of spaced-apart layers of bonded aggregate of suflicient thicknessv to afford material structural strength, said layers being secured together by a less denseand more porous core of bonded brous material extending to the ends of the section and having exposed edge portions, the cores having edge y grooves, and-splines secured in said grooves of the floor and wall.

16. The combination in a. wall structure of a support, a set of panels mounted thereon, each panel consisting of a prefabricated structural section comprising a plurality of spaced-apart layers of bonded aggregate of suicient thickness to aord material structural strength, said layers being secured together by a less dense and more porous core of bonded fibrous material extending to the ends of the section and having exposed edge portions, the panels having registering bottom grooves, and registering vertically extending edge grooves with splines secured'in the vertically extending edge grooves of the adjacent panels.

17. In a building suitable for a dwelling, a wall comprising a plurality of similar prefabricated structural sections comprising a complete wall unit, each section comprising a plurality of spaced-apart layers of bonded aggregate of sufilcient thickness to afford material structural strength, said layers being secured together by a less dense and more porous core of bonded brous material extending to the ends oi' the section and having exposed edge portions, the edges of said sections being interlocked, and said unit being of sui'licient strength to carry the weight imposed upon said wall unit.

' 18. In a building suitable for a dwelling, a wall lcomprising a, plurality of similar prefabricated structural sections comprising a com plete'wall unit,eachsection comprising a plurality of spacedapart layers of bonded aggregate of sulcient thickness to aiord material structural strength, said layers being secured together by a less dense and more porous core of bonded ilbrous material 15 extending to the ends of the section and having exposed edge portions, the adjacent edges of said sections having registering grooves, and splines permanently secured Within said grooves.

19. A wall structure comprising prefabricated 20 structural sections forming a complete wall structure, each section comprising a core oi' bonded iibrcus material extending to the ends of the sectionrand having exposed edge portions, and having a plurality of spaced-apart layers of 25 bonded aggregate and cement of sufiicient thickness to afford material structural strength to the section, said facing layers being more dense and less porous than the bonded fibrous core which secures them together, the bondedbrous 30 cores having grooves, and a spline device engaging registering grooves of the cores of .successive sections.

JAMES H. KENNEDY.

CERTIFICATE or. coRREc'rI-ON.

latent No. 27,097,796.

JAMES H.

KENNEDY Novanber .2,I Y'?u It is hereby certified that error appears inthe printed specification ofthe above numbered patent requiringeorrection as follows: Page il, first column., line 65, claim', for the word "'joints'i read joists; and that the said Letters Patent should be read with this correction thereinthat the same may conformr'to the record of the case inthe Patent Office.

signed and seaied this 12am day of December, A. D. 1957.

(seal) Henry Van :Arsda1e, Actirg Commissioner of" Patents. 

